Caulk, adhesive, potting material and other fluid systems are commonly contained in tubular cartridges of the type having an outlet nozzle at one end and an opposite open end that is closed by a wiper slidably seated against the inside face of the cartridge wall. The material is discharged from the outlet nozzle by advancing the wiper through the cartridge toward the nozzle, which increases the static pressure of the contained material sufficiently to overcome the back pressures against such flow.
Available dispensing tools conventionally utilize a plunger connected to a rod, and a power device activated by a control such as a trigger forces the rod and plunger axially into the open cartridge end and against the wiper. Many dispensing tools are hand held and portable, being powered manually by a ratchet mechanism indexed incrementally upon each trigger squeeze.
Our U.S. Pat. No. 5,263,614 issued on Nov. 23, 1993 from copending patent application having Ser. No. 07/882,836 filed May 14, 1992, discloses manual dispensing tools having spring linkages between the power device and each driven plunger for storing and dissipating unused energy inputted to the power device for maintaining substantially continuous forces on the plunger even between successive trigger squeezes. This overcomes many problems that can occur when an incompressible contained material is being discharged by an incrementally actuated power device.
Our U.S. Pat. No. 5,314,092 issued on May 24, 1994 from patent application having Ser. No. 08/014,114 filed Feb. 5, 1993, discloses a specific dispensing tool plunger having a shiftable O-ring for providing a sealing-venting action to minimize leakage past the wiper and plunger when dicharging the material, while allowing the plunger to be removed from the emptied cartridge for reuse.
Single component fluid systems use only one material cartridge, the material being discharged therefrom via an elongated dispensing tube having the outlet nozzle at its downstream end. Multiple component fluid systems use different material cartridges from which the materials are simultaneously discharged in the precise ratio needed to form the intended composite material, the discharged materials being blended together in an elongated mixing/dispensing tube before being discharged as the composite material via the single outlet nozzle at the downstream end of the mixing/dispensing tube.
Component fluid systems have been successfully used for filling surface cracks in concrete structures to restore structural integrity. Special conduit routing structures can be fitted over the outlet nozzle of the dispensing tube for more accurately directing the discharged material to the intended region of use. One such routing structure is a surface port device, which is in the form of a tube having an enlarged flat base at the outlet end, the base being suited to be bonded by adhesive to the structural surface with the tube bore aligned over a surface crack. The material dispensing tube is then seated against the opposite inlet tube end, to funnel the discharged material via the surface port device directly into the underlying crack.
One major problem that arises is the effort needed for maintaining a nonleaking seated fit between the dispensing tube outlet nozzle and surface port inlet, as reasonably high discharge pressures are common and the user typically must physically hold these seated components together. This is due in part because of the varied types and sizes of commercially available dispensing tubes encountered in every day practical situations.
Specifically, the diameter of the dispensing tubes vary, depending on the material being dispensed, its viscosity and needed rate of mixing and volume of discharge. For example, mixing tubes for multiple component systems typically will be of 1/4, 3/8 or 1/2 inch inner diameter or I.D. and (because of the wall thickness of the tube) a correspondingly larger outer diameter or O.D. and the outlet nozzle end of each such tube might be configurated as a three, four or five smaller stepped cylindrical I.D. and O.D. nose section. Dispensing tubes of single component systems and the smaller multiple component mixing tubes might be of 1/4 inch I.D., and the outlet nozzle end might have a conically tapered nose ending at possibly 1/8 inch O.D. with a correspondingly smaller I.D.
Surface cracks are commonly fixed by surface working a sealing material into the crack along its length, interrupted at spaced locations where different surface port devices would instead be bonded to the surface over the crack. This effectively closes off the crack along the surface, except at the spaced port devices that serve as inlet or outlets. The adjacent port devices would typically be separated by between several inches and several feet. The dispensed material would then be forced into the crack via the port devices, generally starting at the lowest port device on a vertical wall for example, and filling the crack at that location until the material begins to ooze out any higher port device.
A related problem then arises, that is to stop material oozing from the port by closing the port. This is particularly important when the port is located overhead, as in a ceiling.
Still another problem is the compromise of the size and shape of the port base, to provide sufficient surface-device bonding to withstand the injection pressures while not separating from the surface. The conventional circular base shape provides good symmetry of bonding and retention around a concentrically centered material feed tube, but does limit how close the device can be placed to any nearby structure, such as at an interior corner of angled surfaces.
As most cracks are wider at the surface than the crack width deeper in the structure, the material discharge rate should be slow enough to allow deeper material pentration into the crack rather than just along the surface. Common multiple component materials include two-part epoxies, urethanes, silicones, phenolics, acrylics and polyesters.